Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1166 page)

   Approximately 20% of cases of hypothyroidism (second most common cause of hyperprolactinemia). Therefore, serum TSH and T
₄
should always be measured.

   Addison disease

   Polycystic ovaries

   Glucocorticoid excess—normal or moderately elevated prolactin

   Ectopic production of prolactin (e.g., bronchogenic carcinoma, renal cell carcinoma, ovarian teratomas, acute myeloid leukemia)

   Children with sexual precocity—may be increased into pubertal range

   Neurogenic causes (e.g., nursing and breast stimulation, spinal cord lesions, chest wall lesions such as herpes zoster)

   Stress (e.g., surgery, hypoglycemia, vigorous exercise, seizures)

   Pregnancy (increases to 8–20 times normal by delivery, returns to normal 2–4 weeks postpartum unless nursing occurs)

   Lactation

   Chronic renal failure (20–40% of cases; becomes normal after successful renal transplant but not after hemodialysis)

   Liver failure (due to decreased prolactin clearance)

   Idiopathic causes (some probably represent early cases of microadenoma too small to be detected by CT scan)